As wireless network data rates improve using third generation (3G), fourth generation (4G), and WiFi technologies, more and more bandwidth-intensive applications are being developed. A 4G wireless network is an all Internet protocol (IP) wireless network in which different advanced multimedia application services (e.g., voice over IP (VoIP) content, video content, etc.) are delivered over IP. 4G wireless networks include a radio access network (e.g., a long term evolution (LTE) network or an enhanced high rate packet data (eHRPD) network) and a wireless core network (e.g., referred to as an evolved packet core (EPC) network). The LTE network is often called an evolved universal terrestrial radio access network (E-UTRAN). The EPC network is an all-IP packet-switched core network that supports high-speed wireless and wireline broadband access technologies. An evolved packet system (EPS) is defined to include the LTE (or eHRPD) network and the EPC network.
A typical LTE network includes an eNodeB (eNB), a mobility management entity (MME), a serving gateway (SGW), and a packet data network (PDN) gateway (PGW). The current method for selecting a MME, SGW, and PGW for a particular eNB includes hard coding associations based on tracking area codes (TACs) assigned by wireless operators across all geographies and based on access point name (APN).
User equipment (UE) may connect to an appropriate eNB in a LTE network based on signal strength. The eNB forwards a request to the MME to select a SGW and a PGW, as well as a backup SGW and a backup PGW, based on querying a domain name system (DNS) that is manually configured with static mappings. The static mappings associate a TAC to the SGW and the MME, and associate an APN to the PGW. The MME obtains the TAC and the APN from a UE attach message, and uses this information to query the DNS. A minimum of two DNS queries must be performed. The first query obtains name authority pointer (NAPTR) records of correct SGWs, and the second query obtains the associated IP addresses of the SGWs. If any changes occur, these DNS entries must be manually configured and updated, which causes latency and load conditions on the DNS. The MME may select a SGW from a list of SGWs returned by the DNS queries.
Once the SGW is selected, the MME may perform DNS queries to obtain a list of PGWs from which to select based on the APN in the UE attach message. Once the MME selects one of the PGWs from the list, the MME may perform DNS queries to obtain an IP address of the selected PGW. Selection of the PGW causes latencies due to the multiple DNS messages and responses, and causes processing load on the MME and the DNS.
After the SGW and the PGW are selected, the SGW and the PGW may begin processing bearer data traffic. If the SGW or the PGW fails while processing bearer data traffic, the only way for the MME to obtain knowledge of the failure is via timeouts that may be thirty seconds or more. This outage time may not be acceptable in many wireless operator networks, such as LTE networks.